Table 3.
Stomatal conductance for water vapour (gs) and intercellular CO2 concentration (Ci) at 25 °C under growth CO2 concentration, and leaf nitrogen content per unit area (Narea) for rice grown at ambient CO2 (370 µmol mol−1) and at elevated CO2 (570 µmol mol−1)
|
gs (mol m−2 s−1) |
Ci (µmol mol−1) |
Narea (g m−2) |
|||||
|---|---|---|---|---|---|---|---|
| Year | Measurement date | Ambient | FACE | Ambient | FACE | Ambient | FACE |
| 2003 | 18–24 June | 0·23 ± 0·05 | 0·23 ± 0·07 | 268 ± 16 | 435 ± 30*** | 1·91 ± 0·26 | 1·95 ± 0·17 |
| 15–25 July | 0·27 ± 0·09 | 0·16 ± 0·03* | 283 ± 13 | 420 ± 15*** | 1·89 ± 0·19 | 1·78 ± 0·14 | |
| 20–30 August | 0·28 ± 0·07 | 0·18 ± 0·03** | 282 ± 12 | 441 ± 20*** | 2·12 ± 0·18 | 1·73 ± 0·14** | |
| 11–15 September | 0·27 ± 0·09 | 0·20 ± 0·07 | 298 ± 17 | 449 ± 30*** | 1·33 ± 0·07 | 1·25 ± 0·12 | |
| 2004 | 23–28 June | 0·34 ± 0·05 | 0·32 ± 0·04 | 292 ± 3 | 464 ± 9*** | 2·17 ± 0·17 | 2·18 ± 0·11 |
| 21–26 July | 0·32 ± 0·06 | 0·30 ± 0·04 | 293 ± 12 | 458 ± 18*** | 1·95 ± 0·23 | 1·94 ± 0·08 | |
| 21–23 August | 0·41 ± 0·07 | 0·44 ± 0·10 | 318 ± 4 | 499 ± 10*** | 1·88 ± 0·10 | 1·60 ± 0·15** | |
| 14–18 September | 0·25 ± 0·03 | 0·20 ± 0·03* | 329 ± 6 | 509 ± 11*** | 0·97 ± 0·08 | 0·96 ± 0·06 | |
Means ± s.e. (n = 6) are shown. Asterisks indicate significant differences between CO2 treatments: ***, P < 0·0001; **, P < 0·01; *, P < 0·05.